1. Field of the Invention
The present invention relates to cosmetic cleansing agents. Such agents are known as such. They are essentially surface active substances or substance mixtures that are offered to the consumer in various preparations.
2. Discussion of Background Information
Preparations of this type are, for example, bubble baths and shower baths, solid and liquid soaps or so-called “syndets” (synthetic detergents), shampoos, pastes for hand washing, intimate cleansing agents, special cleansing agents for small children and the like.
Surface-active materials—best known as the alkali salts of higher fatty acids, thus, the standard “soaps”—are amphiphilic materials that can emulsify organic non-polar substances in water.
These materials not only wash dirt off skin and hair, but they also irritate skin and mucous membranes more or less intensely, depending on the selection of surfactant or surfactant mixture.
The most common surfactant for cosmetic preparations is sodium lauryl ether sulfate. Although it has good washing power and good compatibility with skin and mucous membranes, sensitive persons should avoid frequent contact with it.
A large number of quite mild surfactants is indeed obtainable. However, prior art surfactants are either mild but clean poorly or else they clean well, but irritate skin and mucous membranes.
Thus, remedial measures for these drawbacks were to be provided.
In a special embodiment, the present invention relates to cleansing preparations for use as a shower preparation.
Such preparations are also known as such. These essentially are surface active substances or substance mixtures that are offered to the consumer in various preparations. Preparations of such a type are characterized generally by a more or less high water content, but can also be, for example, a concentrate.
In general, preparations, which are designated for the shower, do not or hardly differ from bathtub preparations, except that higher viscosity products that do not run off the hand after removal from the container are preferred for shower preparations. This is of lesser practical significance with bathtub preparations.
In a simple water bath without added surfactant, a swelling of the skin's horny layer occurs first, whereby the degree of this swelling depends, for example, on the duration of the bath and its temperature. Simultaneously, water-soluble materials, for example, water-soluble dirt components, but also materials intrinsic to skin, which are responsible for the water-binding capability of the horny layer, are washed off or out. In addition, skin fats are also dissolved to a certain extent, and washed out by surfactants intrinsic to the skin. This causes, after initial swelling, a subsequent distinct drying of the skin that can again be intensified by detersive additives.
These processes are generally negligible in healthy skin, because the skin's protective mechanism can compensate easily for such slight disturbances in the upper skin layers. However, in cases of non-pathological deviations from the normal status, for example, caused by environmental wear and tear damage or irritation, light damage, aged skin, etc., the protective mechanism of the skin's upper layer malfunctions. It is then possibly no longer able to fulfill its objective on its own and must be regenerated by external measures.
Therefore, the object of the present invention was to remedy this shortcoming of the prior art. Further, an object of the invention was to make available bath preparations, but also shower preparations, which, on the one hand, have a strong care effect without, on the other hand, the cleansing effect being inferior.
The present invention further relates to detersive hair-cosmetic preparations, commonly called shampoos. In particular, the present invention relates to hair-cosmetic active ingredient combinations and preparations for care of the hair and scalp.
Washing the hair with aggressive surfactants can also stress the hair, at least its outward appearance, or degrade altogether the outward appearance of the hairdo. For example, certain water-soluble hair constituents (for example, urea, uric acid, xanthine, keratin, glycogen, citric acid, lactic acid) are leached out by the hair wash.
The prior art lacked shampoo formulations which provide care in a satisfactory manner for damaged hair. Therefore, an object was to remedy these disadvantages of the prior art as well.
Gels are conventional and just recently ever more widely spread forms of cosmetic and dermatological preparations.
Cosmetic gels enjoy extreme popularity with the consumer. As they are generally transparent, often may be colored, but just as often clear colorless, they offer the cosmetics developer additional design possibilities, which partially have a functional character, but partially also serve solely for the improvement of outward appearance. Thus, for example, interesting optical effects can be conferred on the product, which is offered to the viewer generally in transparent packaging, by incorporated color pigments, gas bubbles and the like, but also larger objects.
Then, if it is desired that the incorporated object(s), if recognizable as such with the naked eye, or may be given visible shapes in microscopic dimensions, but in an interesting arrangement—for example in the form of artificially produced color streaks, it is desirable that these objects remain fixed in the gel formulation, and not sink to the bottom or in any way undertake other unpleasant migrations in the formulations.
Liquids can differ with respect to their rheological properties in their flow and deformation behavior. Ideal elastic structures sustain from external forces an elastic deformation, that causes, on removal of the external force, a spontaneous complete recovery from the deformation. Ideal viscous structures are changed irreversibly in their form by external forces. The increasing deformation is called flowing. Most liquids are neither ideally viscous nor ideally elastic, but show viscous as well as elastic properties and are therefore called viscoelastic substances.
In most viscoelastic solutions, dispersed particles or gas bubbles are always falling or rising. They have a finite structure relaxation time. This means that the networks in these systems react to a deformation with a corresponding shear stress. This, however, is relaxed to the zero value in a finite time, so that the entire solution is again in a stable state of rest without stress. This means further that these solutions have a defined zero viscosity, and therefore, reach a constant viscosity value at low shear rates.
In contrast to these systems, there are also such in which dispersed particles or gas bubbles do not settle. It is noticed that these systems flow only above a characteristic value. This value is called yield point. On closer consideration of the rheological properties of these systems, it is striking that the memory module is independent of the oscillation frequency in the entire frequency range and is always substantially greater than the loss module.
Conversely, the value of the complex viscosity does not reach a constant value even at the smallest frequencies, but increases further.
Carbopol gels are cross-linked acrylic acid polymers which bear a high number of carboxyl groups. In dissolved form, these structures bind water. Neutralization of the carboxyl groups leads, due to their electrostatic repulsion, to an extension and therefore, swelling of the polymer chains. In this condition, Carbopol gels attain their typical rheological properties, such as, for example, development of a yield point.
The action of the development of a yield point is based, therefore, on the electrostatic repulsion of the carboxyl groups, Additional electrolytes shield these charges. Consequently the networks collapse, the yield point breaks down. Particles or gas bubbles can no longer be held in suspension.
Surfactants act like electrolytes. Therefore, it was not possible until now to formulate good, foaming cleansing products having a correspondingly high surfactant content and containing, as the base, clear Carbopol gels having a yield point.
The prior art does indeed already disclose corresponding systems with xanthan gum (for example, EP-A 738 509). These have, however, worse cosmetic properties, relative to the feel of the skin, before and after use. Furthermore, only low viscosities can be achieved at identical use concentration. The design of a gel, which, in addition, has suitable flow properties, usually presents no extremely great difficulties to one of skill in the art, unless high surfactant concentrations are to be achieved, as a rule, a basic requirement in cleansing products. The disadvantage of such high surfactant concentrations is that mostly only cloudy or even opaque products are obtained.
WO 01/19946 discloses detersive recipes that contain a conditioner in addition to a gel-former. WO 01/176552 discloses detersive recipes which involve a combination of certain thickeners with acyl glutamates. However, these publications could not point to the present invention.
Another disadvantage of prior art preparations was the poor compatibility of the gel-former used for stabilization with electrolytes in general and ionic surfactants in particular. Such preparations have correspondingly poor product performance, such as, for example, weak foam formation and an unpleasant feel on skin. Furthermore, such products can mostly not be called truly clear.
To be sure, electrolyte-tolerant and surfactant-tolerant gel-formers do exist by all means, but again as a rule, highly impair skin-feeling, because they must be used in comparatively high concentrations. The object of the present invention was, therefore, to find formulations, which permit preparing elastic, surfactant-containing gels having a satisfactory yield point while simultaneously avoiding a dull skin-feeling during and after use.
In addition, for the development of a yield point that suffices to stably suspend different particles, gas bubbles or effect materials, quantities of gel-formers are used, which also lead to a considerable increase in product viscosity in addition to the development of a yield point or an increase in elastic modulus. This impairs removal by the consumer, draining residues, distributability of the product, and foaming during use.
Therefore, the object of the present invention was to find ways that permit the preparation of elastic, surfactant-containing gels having a satisfactory yield point with simultaneously comparatively low viscosity.
Thus, remedies for these disadvantages of the prior art were to be provided as well.